Looking for a way to "Spotlight" an area

We have some existing PDF files we where would like to take some areas and "Spotlight" them. In other words, ghost out the rest of the drawing but keep the spotlighted areas in their original black-and-white condition. Is there an easy way to do this?

One of my colleagues has put in a series of intricate text boxes and changed the opacity to ghost out the area behind.

You could perhaps take a snapshot of what you want to keep normal, place it over the original part of the drawing, then use one big rectangle with increased opacity to grey out everything behind the snapshot?

In addition to coryvoire's suggestion about using snapshots, you could just use the dimmer feature (Ctrl+F5) to gray out the background to make your markups stand out. This saves you the step of creating a big rectangle in the background. You can also adjust the opacity of the dimmer function from 0 to 100 in 10 percent increments. If you want to print this, make sure you check the box "Dim Page Content" in the print dialog box.

To take it a step further, you could create a layer and paste all your markups (snapshots) there, so it would be easy to toggle viewing and printing off the layer in one step, or just to keep them organized.

p.s. After you take a snapshot, Ctrl+Shift+V pastes the snapshot in the exact same position, so you get a perfect overlay.